The Early Development of the Casale Process for the Production of Synthetic Ammonia (1917-1922). The protagonists, the technology, and a link between Italy and the United States

The Haber-Bosch process for the industrial synthesis of ammonia, originally intended for use in manufacture of nitrogen fertilizers, was inaugurated by BASF of Germany in 1913. During the First World War the process proved to be of tremendous value to Germany for the production of munitions. This was appreciated by the Allied nations, but, despite great efforts, they were unable to replicate the process prior to the cessation of hostilities. Notwithstanding tremendous postwar demand for nitrogen products to ensure national security in both munitions and fertilizers, BASF refused to license its ammonia process. This ultimately forced inventors and firms elsewhere to innovate based on their wartime research efforts. This paper provides an account of the emergence of the first successful rival to the BASF Haber-Bosch synthetic ammonia process, that of the Italian inventor Luigi Casale. To accomplish this goal, Casale in 1917 gained the support of the wartime chemical manufacturer Idros, at Terni, north of Rome, headed by the Franco-American entrepreneur René Leprestre. Better facilities for development of a working process, including byproduct hydrogen, were available at the works of the Rumianca company. Casale moved there in 1919. Leprestre brought in representatives of a group of investors from the United States to observe Casale’s process in action at the Rumianca works. However, disputes quickly emerged. Agreements were broken, followed by lengthy litigation, and the return of Casale to Idros at Terni. At Terni there were different problems. There, barriers to the supply of electricity were created, in part because the ammonia technology was perceived to be highly disruptive to another, well developed, local nitrogen process, that of calcium cyanamide. Compromises were reached. The outcome was the almost simultaneous foundation in 1921 of two companies, Ammonia Casale SA, in Lugano, Switzerland, which handled international licensing, and the Società Italiana per l’Ammoniaca Sintetica (SIAS) which absorbed the Idros works. In 1922 SIAS acquired a mothballed hydroelectric factory at Nera Montoro. It would serve as the industrial testing site for improvements in Casale’s process. The widespread, and rapid, dispersal of Luigi Casale’s highly successful synthetic ammonia process became an outstanding example of technology transfer from Italy during the early 1920s. This transfer included, through Leprestre, to the United States, as recently described in Substantia. The origins of the transatlantic interest can be discerned in the very earliest attempts by Casale to develop his novel ammonia technology, as described here.